Separator and electrochemical device including the same

Abstract

One aspect of the present invention provides a separator including a porous substrate, and a heat-resistant layer disposed on at least one surface of the porous substrate and including inorganic particles, wherein the ratio (F2/F1) of air permeability (F2, sec/100 mL) in a curved surface with a radius of curvature of 10 mm of the separator to the air permeability (F1, sec/100 mL) in a flat surface of the separator is 1.5 or less, and an electrochemical device including the same.

1 . A separator comprising a porous substrate, and a heat-resistant layer which is disposed on at least one surface of the porous substrate and comprises inorganic particles,
 wherein the ratio (F2/F1) of air permeability (F2, sec/100 mL) in a curved surface of the separator with a radius of curvature of 10 mm to air permeability (F1, sec/100 mL) in a flat surface of the separator is 1.5 or less.   
     
     
         2 . The separator of  claim 1 , wherein the porous substrate comprises one selected from the group consisting of polyethylene, polypropylene, polybutylene, polymethyl pentene, ethylene vinyl acetate, ethylene butyl acrylate, ethylene ethyl acrylate, and a combination or copolymer of two or more thereof. 
     
     
         3 . The separator of  claim 1 , wherein the separator comprises a first heat-resistant layer disposed on one surface of the porous substrate, and a second heat-resistant layer included on the other surface of the porous substrate, and
 the density of the first heat-resistant layer is smaller than that of the second heat-resistant layer.   
     
     
         4 . The separator of  claim 3 , wherein the first and second heat-resistant layers face the inside and outside of a battery in which an electrode assembly having electrodes on both surfaces of the separator is wound or bent according to a predetermined specification, respectively. 
     
     
         5 . The separator of  claim 4 , wherein the first heat-resistant layer comprises first inorganic particles and a first binder that adheres at least some of the first inorganic particles at predetermined intervals,
 the first binder comprises a water-insoluble polymer,   the content of the water-insoluble polymer in the first binder is 40 to 90 wt %, and   the density of the first heat-resistant layer is 1.6 g/m 2  or less.   
     
     
         6 . The separator of  claim 5 , wherein the second heat-resistant layer comprises second inorganic particles and a second binder that adheres at least some of the second inorganic particles at predetermined intervals,
 the second binder comprises a water-soluble polymer,   the content of the water-soluble polymer in the second binder is 70 wt % or more, and   the density of the second heat-resistant layer is 1.7 g/m 2  or more.   
     
     
         7 . The separator of  claim 5 , wherein the first inorganic particles are one selected from the group consisting of SiO 2 , AlO(OH), Mg(OH) 2 , Al(OH) 3 , TiO 2 , BaTiO 3 , Li 2 O, LiF, LiOH, Li 3 N, BaO, Na 2 O, Li 2 CO 3 , CaCO 3 , LiAlO 2 , Al 2 O 3 , SiO, SnO, SnO 2 , PbO 2 , ZnO, P 2 O 5 , CuO, MoO, V 2 O 5 , B 2 O 3 , Si 3 N 4 , CeO 2 , Mn 3 O 4 , Sn 2 P 2 O 7 , Sn 2 B 2 O 5 , Sn 2 BPO 6 , and a combination of two or more thereof. 
     
     
         8 . The separator of  claim 6 , wherein the second inorganic particles are one selected from the group consisting of SiO 2 , AlO(OH), Mg(OH) 2 , Al(OH) 3 , TiO 2 , BaTiO 3 , Li 2 O, LiF, LiOH, Li 3 N, BaO, Na 2 O, Li 2 CO 3 , CaCO 3 , LiAlO 2 , Al 2 O 3 , SiO, SnO, SnO 2 , PbO 2 , ZnO, P 2 O 5 , CuO, MoO, V 2 O 5 , B 2 O 3 , Si 3 N 4 , CeO 2 , Mn 3 O 4 , Sn 2 P 2 O 7 , Sn 2 B 2 O 5 , Sn 2 BPO 6 , and a combination of two or more thereof. 
     
     
         9 . The separator of  claim 5 , wherein the water-insoluble polymer is one selected from the group consisting of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichloroethylene, polymethylmethacrylate, polyacrylonitrile, ethylene vinyl acetate, polyvinyl butyral, an acrylonitrile-acrylic acid copolymer, an ethylene-acrylic acid copolymer, a styrene-butadiene copolymer, an alkyl acrylate-acrylonitrile copolymer, an acryl-styrene copolymer, acrylic rubber, and a combination of two or more thereof. 
     
     
         10 . The separator of  claim 6 , wherein the water-soluble polymer is one selected from the group consisting of polyacrylic acid, polyvinylpyrrolidone, polyvinyl acetate, polyimide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, hydroxyethyl cellulose, cyanoethyl sucrose, pullulan, carboxymethylcellulose, polyvinyl alcohol, polyethylene oxide, polyethylene glycol, and a combination of two or more thereof. 
     
     
         11 . An electrochemical device, comprising the separator of  claim 1 .